I'm beginning my exhaust project here real shortly, for a 98 XJ.

From fleabay, my Manifold.

From Performance Curve, my cat.

From Autozone, my Muffler.

Unlisted items need not be replaced. There's no damages. My exhaust measures 2.5", with the exception of the tail pipe, 2.25".

This question may be stupid... On my current cat (and I know we're not suppose to be talking about cats) my o2 Sensor mounts in behind it, as does probably everyone's here. Looking at the cats on Performance-curve... The standard duty doesn't post, or show where the o2 sensor would screw in at. There's an air line, but no o2 plug. The "Thunder bolt" spin cats have an o2 plug in them however (I was considering one of these as well), but not the standard duty.

Tried contacting mudfrog here a while ago via PM, no response. Anyone else familiar with these?

 

There very well may not be.

But just about any exhaust shop should be able to weld a bung in for you.

 

That was one of my concerns...

Currently my exhaust is all clamped on. I was hoping to keep it this way, considering if something breaks, I wouldn't have to cut it off and take it back to a shop. I can swap parts out as I need to.

 

Band clamps r your friend....u can get crazy, then change your mind if u want or go back to stock, I guess (but who'd want to do that, LOL).

 

That's pretty awesome! Where do you find those at? And how much $?

 

you can get them on performance curve and most auto parts stores for $10-15 ea? They are a bit pricey compared to the normal exhaust clamps. The cat you are looking at is only about $10 more with the bung welded in, unless you can cut and weld one in yourself I doubt you can get one cheaper.

 

The o2 sensor on my current cat, which is a standard duty, is mounted onto the pipe coming out the back. On this thunderbolt, the hole is mounted right after the ceramic block. Will that space being closer, make a difference?

 

No it will not make a difference, there is plenty of slack in the line if the hole isn't quite where it used to be. The proximity to the ceramic block shouldn't matter as the sensor really doesn't do a whole lot. The only thing to watch out for if you did it like me, is if you have a piece of pipe to make up the difference between the cat and muffler. Just don't let the pipe slide up into where the sensor will be for obvious reasons.

 

Jeggs or Summit, about $7 ea., iirc,....they're stainless steel, last forever. They also have the mandrel bent tubing and it's also available in stainless if u want to get crazy. I just went with the aluminized stuff.

 

I never suggested you have the entire system welded.

Just take the one piece to the shop. They will drill a hole where ever you tell them to, within reason, and weld in a threaded bung for the o2 sensor.

But it appears as though you hve figured it out.